Electronically switching latching micro-magnetic relay and method of operating same

ABSTRACT

According to various embodiments of the invention, a relay is suitably formed to exhibit an open state and a closed state. The relay is operated by providing a cantilever sensitive to magnetic fields such that the cantilever exhibits a first state corresponding to the open state of the relay and a second state corresponding to the closed state of the relay. A first magnetic field may be provided to induce a magnetic torque in the cantilever, and the cantilever may be switched between the first state and the second state with a second magnetic field that may be generated by, for example, a conductor formed on a substrate with the relay.

This application claims priority of Provisional Application Serial No.60/155,757 filed Sep. 23, 1999.

Partial funding for the development of this invention was provided byU.S. Government Grant Number Air Force SBIR F29601-99-C-0101,Subcontract No. ML99-01 with the United States Sir. Force; and theUnited States Government may own certain rights to this invention.

FIELD OF THE INVENTION

The present invention relates to relays. More specifically, the presentinvention relates to latching micro-magnetic relays with low powerconsumption and to methods of formulating, and operating micro-magneticrelays.

BACKGROUND OF THE INVENTION

Relays are typically electrically controlled two-state devices that openand close electrical contacts to effect operation of devices in anelectrical circuit. Stated another way, relays typically function asswitches that activate or de-activate portions of an electrical, opticalor other device. Relays are commonly used in many applications includingtelecommunications, radio frequency (RF) communications, portableelectronics, consumer and industrial electronics, aerospace, and othersystems.

Although the earliest relays were mechanical or solid-state devices,recent developments in micro-electro-mechanical systems (MEMS)technologies and microelectronics manufacturing have mademicro-electrostatic and micro-magnetic relays possible. Suchmicro-magnetic relays typically include an electromagnet that energizesan armature to make or break an electrical contact. When the magnet isde-energized, a spring or other mechanical force typically restores thearmature to a quiescent position. Such relays typically exhibit a numberof marked disadvantages, however, in that they generally exhibit only asingle stable output (i.e. the quiescent state) and they are notlatching (i.e. they do not retain a constant output as power is removedfrom the relay). Moreover, the spring required by conventionalmicro-magnetic relays may degrade or break over time.

Another micro-magnetic relay is described in U.S. Pat. No. 5,847,631issued to Taylor et al. on Dec. 8, 1998, the entirety of which isincorporated herein by reference. The relay disclosed in this referenceincludes a permanent magnet and an electromagnet for generating amagnetic field that intermittently opposes the field generated by thepermanent magnet. Although this relay purports to be bi-stable, therelay requires consumption of power in the electromagnet to maintain atleast one of the output states. Moreover, the power required to generatethe opposing field would be significant, thus making the relayunsuitable for use in space, portable electronics, and otherapplications that demand low power consumption.

A bi-stable, latching relay that does not require power to hold thestates is therefore desired. Such a relay should also be reliable,simple in design, low-cost and easy to manufacture.

SUMMARY OF THE INVENTION

According to various embodiments of the invention, a relay is suitablyformed to exhibit an open state and a closed state. The relay isoperated by providing a cantilever sensitive to magnetic fields suchthat the cantilever exhibits a first state corresponding to the openstate of the relay and a second state corresponding to the closed stateof the relay. A first magnetic field may be provided to induce amagnetic torque in the cantilever, and the cantilever may be switchedbetween the first state and the second state with a second magneticfield that may be generated by, for example, a conductor formed on asubstrate with the relay.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The above and other features and advantages of the present invention arehereinafter described in the following detailed description ofillustrative embodiments to be read in conjunction with the accompanyingdrawing figures, wherein like reference numerals are used to identifythe same or similar parts in the similar views, and:

FIG. 1A is a side view of an exemplary embodiment of a latching relay;

FIG. 1B is a top view of an exemplary embodiment of a latching relay;

FIGS. 2A-H are side views showing an exemplary technique formanufacturing a latching relay;

FIG. 3A is a side view of a second exemplary embodiment of a latchingrelay;

FIG. 3B is a top view of a second exemplary embodiment of a latchingrelay;

FIG. 3C is a perspective view of an exemplary cantilever suitable foruse with the second exemplary embodiment of a latching relay;

FIG. 4A is a side view of a third exemplary embodiment of a latchingrelay;

FIG. 4B is a top view of a third exemplary embodiment of a latchingrelay;

FIGS. 4C and 4D are perspective views of exemplary cantilevers suitablefor use with the third exemplary embodiment of a latching relay; and

FIG. 5 is a side view of a fourth exemplary embodiment of a latchingrelay.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

It should be appreciated that the particular implementations shown anddescribed herein are examples of the invention and are not intended tootherwise limit the scope of the present invention, in any way. Indeed,for the sake of brevity, conventional electronics manufacturing, MEMStechnologies and other functional aspects of the systems (and componentsof the individual operating components of the systems) may not bedescribed in detail herein. Furthermore, for purposes of brevity, theinvention is frequently described herein as pertaining to amicro-electronically-machined relay for use in electrical or electronicsystems. It should be appreciated that many other manufacturingtechniques could be used to create the relays described herein, and thatthe techniques described herein could be used in mechanical relays,optical relays or any other switching device. Further, the techniqueswould be suitable for application in electrical systems, opticalsystems, consumer electronics, industrial electronics, wireless systems,space applications, or any other application. Moreover, it should beunderstood that the spatial descriptions made herein are for purposes ofillustration only, and that practical latching relays may be spatiallyarranged in any orientation or manner. Arrays of these relays can alsobe formed by connecting them in appropriate ways and with appropriatedevices.

A Latching Relay

FIGS. 1A and 1B show side and top views, respectively, of a latchingrelay. With reference to FIGS. 1A and 1B, an exemplary latching relay100 suitably includes a magnet 102, a substrate 104, an insulating layer106 housing a conductor 114, a contact 108 and a cantilever 112positioned above substrate by a staging layer 110.

Magnet 102 is any type of magnet such as a permanent magnet, anelectromagnet, or any other type of magnet capable of venerating amagnetic field H_(o) 134, as described more fully below. In an exemplaryembodiment, magnet 102 is a Model 59-P09213T001 magnet available fromthe Dexter Magnetic Technologies corporation of Fremont, Calif. althoughof course other types of magnets could be used. Magnetic field 134 maybe generated in any manner and with any magnitude, such as from about 1Oersted to 10⁴ Oersted or more. In the exemplary embodiment shown inFIG. 1, magnetic field H_(o) 134 may be generated approximately parallelto the Z axis and with a magnitude on the order of about 370 Oersted,although other embodiments will use varying orientations and magnitudesfor magnetic field 134. In various embodiments, a single magnet 102 maybe used in conjunction with a number of relays 100 sharing a commonsubstrate 104.

Substrate 104 is formed of any type of substrate material such assilicon, gallium arsenide, glass, plastic, metal or any other substratematerial. In various embodiments, substrate 104 may be coated with aninsulating material (such as an oxide) and planarized or otherwise madeflat. In various embodiments, a number of latching relays 100 may sharea single substrate 104. Alternatively, other devices (such astransistors, diodes, or other electronic devices) could be formed uponsubstrate 104 along with one or more relays 100 using, for example,conventional integrated circuit manufacturing techniques. Alternatively,magnet 102 could be used as a substrate and the additional componentsdiscussed below could be formed directly on magnet 102. In suchembodiments, a separate substrate 104 may not be required.

Insulating layer 106 is formed of any material such as oxide or anotherinsulator. In an exemplary embodiment, insulating layer is formed ofProbimide 7510 material. Insulating layer 106 suitably houses conductor114. Conductor 114 is shown in FIGS. 1A and 1B to be a single conductorhaving two ends 126 and 128 arranged in a coil pattern. Alternateembodiments of conductor 114 use single or multiple conducting segmentsarranged in any suitable pattern such as a meander pattern, a serpentinepattern, a random pattern, or any other pattern. Conductor 114 is formedof any material capable of conducting electricity such as gold, silver,copper, aluminum, metal or the like. As conductor 114 conductselectricity, a magnetic field is generated around conductor 114 asdiscussed more fully below.

Cantilever 112 is any armature, extension, outcropping or member that iscapable of being affected by magnetic force. In the embodiment shown inFIG. 1A, cantilever 112 suitably includes a magnetic layer 118 and aconducting layer 120. Magnetic layer 118 may be formulated of permalloy(such as NiFe alloy) or any other magnetically sensitive material.Conducting layer 120 may be formulated of gold, silver, copper,aluminum, metal or any other conducting material. In variousembodiments, cantilever 112 exhibits two states corresponding to whetherrelay 100 is “open” or “closed”, as described more fully below. In manyembodiments, relay 100 is said to be “closed” when a conducting layer120 connects staging layer 110 to contact 108. Conversely, the relay maybe said to be “open” when cantilever 112 is not in electrical contactwith contact 108. Because cantilever 112 may physically move in and outof contact with contact 108, various embodiments of cantilever 112 willbe made flexible so that cantilever 112 can bend as appropriate.Flexibility may be created by varying the thickness of the cantilever(or its various component layers), by patterning or otherwise makingholes or cuts in the cantilever, or by using increasingly flexiblematerials. Alternatively, cantilever 112 can be made into a “hinged”arrangement such as that described below in conjunction with FIG. 3.Although of course the dimensions of cantilever 112 may varydramatically from implementation to implementation, an exemplarycantilever 112 suitable for use in a micro-magnetic relay 100 may be onthe order of 10-1000 microns in length, 1-40 microns in thickness, and2-600 microns in width. For example, an exemplary cantilever inaccordance with the embodiment shown in FIG. 1 may have dimensions ofabout 600 microns×10 microns×50 microns, or 1000 microns×600 microns×25microns, or any other suitable dimensions.

Contact 108 and staging layer 110 are placed on insulating layer 106, asappropriate. In various embodiments, staging layer 110 supportscantilever 112 above insulating layer 106, creating a gap 116 that maybe vacuum or may become filled with air or another gas or liquid such asoil. Although the size of cap 116 varies widely with differentimplementations, an exemplary gap 116 may be on the order of 1-100microns, such as about 20 microns. Contact 108 may receive cantilever112 when relay 100 is in a closed state, as described below. Contact 108and staging layer 110 may be formed of any conducting, material such asgold, gold alloy, silver, copper, aluminum, metal or the like. Invarious embodiments, contact 108 and staging layer 110 are formed ofsimilar conducting materials, and the relay is considered to be “closed”when cantilever 112 completes a circuit between staging layer 110 andcontact 108. Other embodiments use different formulations for contact108 and staging layer 110, such as those discussed below in conjunctionwith FIGS. 3 and 4. In certain embodiments wherein cantilever 112 doesnot conduct electricity, staging layer 110 may be formulated ofnon-conducting material such as Probimide material, oxide, or any othermaterial. Additionally, alternate embodiments may not require staginglayer 110 if cantilever 112 is otherwise supported above insulatinglayer 106.

Principle of Operation

In a broad aspect of the invention, magnet 102 generates a magneticfield H_(o) 134 that induces a magnetization (m) in cantilever 112. Themagnetization suitably creates a torque on cantilever 112 that forcescantilever 112 toward contact 108 or away from contact 108, dependingupon the direction of the magnetization, thus placing relay 100 into anopen or closed state. The direction of magnetization in cantilever 112may be adjusted by a second magnetic field generated by conductor 114 asappropriate, and as described more fully below.

With continued reference to FIGS. 1A and 1B, magnetic field H_(o) 134may be applied by magnet 102 primarily in the direction parallel to theZ-axis such that the field is perpendicular to the primary dimension(e.g. the length) of cantilever 112. Magnetic field 134 suitably inducesa magnetization in cantilever 112, which may be made of soft magneticmaterial. Because of the geometry of cantilever 112, the magnetizationin cantilever 112 suitably aligns along the long axis of the cantilever,which is the length of cantilever 112 (parallel to the X-axis) in FIG.1.

The orientation of the magnetization in cantilever 112 is suitablydependent upon the angle (alpha) between the applied magnetic field 134and the long axis of cantilever 112. Specifically, when the angle(alpha) is less than 90 degrees, the magnetic moment (m) in cantilever112 points from end 130 of cantilever 112 toward end 132. Theinteraction between the magnetic moment and magnetic field H_(o) 134thus creates a torque in a counter-clockwise direction about end 130 ofcantilever 112 that moves end 132 upward, as appropriate, thus openingthe circuit between staging layer 110 and contact 108. Conversely, whenthe angle (alpha) is greater than 90 degrees, the magnetic moment (m) incantilever 112 points from end 132 toward end 130, creating a clockwisetorque about end 130. The clockwise torque moves end 132 downward tocomplete the circuit between staging layer 110 and contact 108. Becausethe magnetization (m) of cantilever 112 does not change unless the angle(alpha) between the long axis of cantilever 112 and the applied magneticfield 134 changes, the applied torque will remain until an externalperturbation is applied. Elastic torque of the cantilever or a stopper(such as the contact) balances the applied magnetic torque, and thusrelay 100 exhibits two stable states corresponding to the upward anddownward positions of cantilever 112 (and therefore to the open andclosed states, respectively, of relay 100).

Switching is accomplished by any suitable switching technique. In anexemplary embodiment, switching is accomplished by generating a secondmagnetic field that has a component along the long axis of cantilever112 that is strong enough to affect the magnetization (m) of cantilever112. In the embodiment shown in FIG. 1, the relevant component of thesecond magnetic field is the component of the field along the X-axis.Because the strength of the second magnetic field along the long axis ofcantilever 112 is of primary concern, the overall magnitude of thesecond magnetic field is typically significantly less than the magnitudeof magnetic field 134 (although of course fields of any strength couldbe used in various embodiments). An exemplary second magnetic field maybe on the order of 20 Oersted, although of course stronger or weakerfields could be used in other embodiments.

The second magnetic field may be generated through, for example, amagnet such as an electronically-controlled electromagnet.Alternatively, the second magnetic field may be generated by passing acurrent through conductor 114. As current passes through conductor 114,a magnetic field is produced in accordance with a “right-hand rule”. Forexample, a current flowing from point 126 to point 128 on conductor 114(FIG. 1B) typically generates a magnetic field “into” the center of thecoil shown, corresponding to field arrows 122 in FIG. 1A. Conversely, acurrent flowing from point 128 to point 126 in FIG. 1 generates amagnetic field flowing “out” of the center of the coil shown,corresponding to dashed field arrows 124 in FIG. 1A. The magnetic fieldmay loop around the conductor 114 in a manner shown also in FIG. 1A,imposing a horizontal (X) component of the magnetic field on thecantilever 112.

By varying the direction of the current or current pulse flowing inconductor 114, then, the direction of the second magnetic field can bealtered as desired. By altering the direction of the second magneticfield, the magnetization of cantilever 112 may be affected and relay 100may be suitably switched open or closed. When the second magnetic fieldis in the direction of field arrows 122, for example, the magnetizationof cantilever 112 will point toward end 130. This magnetization createsa clockwise torque about end 130 that places cantilever 112 in a “down”state that suitably closes relay 100. Conversely, when the secondmagnetic field is in the direction of dashed field arrows 124, themagnetization of cantilever 112 points toward end 132, and acounter-clockwise torque is produced that places cantilever 112 in an“up” state that suitably opens relay 100. Hence, the “up” or “down”state of cantilever 112 (and hence the “open” or “closed” state of relay100) may be adjusted by controlling the current flowing throughconductor 114. Further, since the magnetization of cantilever 112remains constant without external perturbation, the second magneticfield may be applied in “pulses” or otherwise intermittently as requiredto switch the relay. When the relay does not require a change of state,power to conductor 114 may be eliminated, thus creating a bi-stablelatching relay 100 without power consumption in quiescent states. Such arelay is well suited for applications in space, aeronautics, portableelectronics, and the like.

Manufacturing a Latching Relay

FIG. 2 includes a number of side views showing an exemplary techniquefor manufacturing a latching relay 100. It will be understood that theprocess disclosed herein is provided solely as an example of one of themany techniques that could be used to formulate a latching relay 100.

An exemplary fabrication process suitably begins by providing asubstrate 102, which may require an optional insulating layer. Asdiscussed above, any substrate material could be used to create alatching relay 100, so the insulating layer will not be necessary if,for example, an insulating substrate is used. In embodiments thatinclude an insulating layer, the layer may be a layer of silicon dioxide(SiO₂) or other insulating material that may be on the order of 1000angstroms in thickness. Again, the material chosen for the insulatingmaterial and the thickness of the layer may vary according to theparticular implementation.

With reference to FIG. 2A, conductor 114 is suitably formed on substrate104. Conductor 114 may be formed by any technique such as deposition(such as e-beam deposition), evaporation, electroplating or electrolessplating, or the like. In various embodiments, conductor 114 is formed ina coil pattern similar to that shown in FIG. 1. Alternatively, conductor114 is formed in a line, serpentine, circular, meander, random or otherpattern. An insulating layer 106 may be spun or otherwise applied tosubstrate 104 and conductor 114 as shown in FIG. 2B. Insulating layer106 may be applied as a layer of photoresist, silicon dioxide,Probimide-7510 material, or any other insulating material that iscapable of electrically isolating the top devices. In variousembodiments, the surface of the insulating material is planarizedthrough any technique such as chemical-mechanical planarization (CMP).

Contact pads 108 and 110 may be formed on insulating layer 106 throughany technique such as photolithography, etching, or the like (FIG. 2C).Pads 108 and 110 may be formed by depositing one or more layers ofconductive material on insulating layer 106 and then patterning the padsby wet etching, for example. In an exemplary embodiment, pads 108 and110 suitably include a first layer of chromium (to improve adhesion toinsulating layer 106) and a second layer of gold, silver, copper,aluminum, or another conducting material. Additional metal layers may beadded to the contacts by electroplating or electroless plating methodsto improve the contact reliability and lower the resistance.

With reference to FIG. 2D, the contact pads 108 and 110 may be suitablycovered with a layer of photoresist, aluminum, copper, or other materialto form sacrificial layer 202. An opening 206 in sacrificial layer 202over the cantilever base areas may be defined by photolithography,etching, or another process. Cantilever 112 may then be formed bydepositing, sputtering or otherwise placing one or more layers ofmaterial on top of sacrificial layer 202 and extending over the opening206, as shown in FIG. 2E. In an exemplary embodiment, a base layer 204of chromium or another metal may be placed on sacrificial layer 202 toimprove adhesion, and one or more conducting layers 120 may be formed aswell. Layers 204 and 120 may be formed by, for example, depositionfollowed by chemical or mechanical etching. Layer 120 may be thickenedby adding another conductor layer (such as gold, gold alloy, etc.) byelectroplating or electroless plating methods. Cantilever 112 is furtherformed by electroplating or otherwise placing a layer 118 of permalloy(such as NiFe permalloy) on top of conducting layer 120, as shown inFIG. 2F. The thickness of the permalloy layer 118 may be controlled byvarying the plating current and time of electroplating. Electroplatingat 0.02 amperes per square centimeters for a period of 60 minutes, forexample, may result in an exemplary permalloy layer thickness of about20 microns. In various embodiments, an additional permalloy layer 306(shown in FIG. 3) may be electroplated on top of cantilever 112 toincrease the responsiveness of cantilever 112 to magnetic fields.

With reference to FIG. 2G, sacrificial layer 202 may be removed by, forexample, wet or dry (i.e. oxygen plasma) releasing to create gap 116between cantilever 112 and insulating layer 106. In various embodiments,adhesion layer 204 is suitably removed with micro-mechanical etching oranother technique to form relay 100 (FIG. 2H). Relay 100 may then bediced, packaged with magnet 102 (shown in FIG. 1) or otherwise processedas appropriate. It should be understood that the permanent magnet 102can also be fabricated directly on the substrate, placed on top of thecantilever, or the coil and the cantilever can be fabricated directly ona permanent magnet substrate.

Alternate Embodiments of Latching Relays

FIGS. 3 and 4 disclose alternate embodiments of latching relays 100.FIGS. 3A and 3B show side and top views, respectively, of an alternateembodiment of a latching relay that includes a hinged cantilever 112.The perspective of FIGS. 3A and 3B is rotated 90 degrees in the X-Yplane from the perspective shown in FIGS. 1A and 1B to better show thedetail of the hinged cantilever. With reference to FIGS. 3A and 3B, ahinged cantilever 112 suitably includes one or more strings 302 and 304that support a magnetically sensitive member 306 above insulating layer106. Member 306 may be relatively thick (on the order of about 50microns) compared to strings 302 and 304, which may be formed ofconductive material. As with the relays 100 discussed above inconjunction with FIG. 1, relays 100 with hinged cantilevers may beresponsive to magnetic fields such as those generated by magnet 102 andconductor 114. In various embodiments, one or both of strings 302 and304 are in electrical communication with contact pad 108 when the relayis in a “closed” state. Of course, any number of strings could be used.For example, a single string could be formulated to support the entireweight of member 306. Additionally, the strings may be located at anypoint on member 306. Although FIG. 3 shows strings 302 and 304 near thecenter of member 306, the strings could be located near the end ofmember 306 toward contact 108 to increase the torque produced by magnet102, for example.

FIG. 3C is a perspective view of an exemplary cantilever 112 suitablefor use with the embodiments shown in FIGS. 3A and 3B. Cantilever 112suitably includes member 306 coupled to conducting layer 120. Holes 310and/or 312 may be formed in conducting layer 120 to improve flexibilityof cantilever 112, and optional contact bumps 308 may be formed on thesurface of conducting layer 120 to come into contact with contact 108.Strings 302 and 304 (not shown in FIG. 3C) may be affixed or otherwiseformed on cantilever 112 at any position (such as in the center ofconducting layer 120 or at either end of conducting layer 120) asappropriate. Alternatively, the strings may be formed of non-conductingmaterials and cantilever 112 may provide a conducting path between twoseparate conductors touched simultaneously by the cantilever in theclosed state, as discussed below.

FIGS. 4A and 4B are side and top views, respectively, of an alternateembodiment of a latching relay 100. As shown in the Figure, variousembodiments of cantilever 112 may not directly conduct electricity fromstaging layer 110 to contact 108. In such embodiments, a conductingelement 402 may be attached to cantilever 112 to suitably provideelectrical contact between contacts 108 and 408 when relay 100 is in a“closed” state. FIGS. 4C and 4D are perspective views of alternateexemplary embodiments of cantilever 112. In such embodiments, cantilever112 may include a magnetically sensitive portion 118 separated from aconducting portion 402 by an insulating layer 410, which may be adielectric insulator, for example. Optional contact bumps 308 may alsobe formed on conducting portion 402 as shown. When cantilever 112 is ina state corresponding to the “closed” state of relay 100, current mayfollow the path shown by arrows 412 between contact pads 108 and 408, asappropriate.

FIG. 5 is a side view of an alternate exemplary embodiment of relay 100.With reference to FIG. 5, a relay 100 may include a magnet 102, asubstrate 104 and a cantilever 112 as described above (for example inconjunction with FIG. 1). In place of (or in addition to) conductor 114formed on substrate 104, however, conductor 114 may be formed on asecond substrate 504, as shown. Second substrate 504 may be any type ofsubstrate such as plastic, glass, silicon, or the like. As with theembodiments described above, conductor 114 may be coated with aninsulating layer 506, as appropriate. To create a relay 100, the variouscomponents may be formed on substrates 104 and 504, and then thesubstrates may be aligned and positioned as appropriate. The twosubstrates 104 and 504 (and the various components formed thereon) maybe separated from each other by spacers such as spacers 510 and 512 inFIG. 5, which may be formed of any material.

With continued reference to FIG. 5, contact 108 may be formed oninsulating layer 106, as described above. Alternatively, contact 508 maybe formed on second substrate 504, as shown in FIG. 5 (of coursecantilever 112 may be reformulated such that a conducting portion ofcantilever 112 comes into contact with contact 508). In otherembodiments, contacts 108 and 508 may both be provided such that relay100 is in a first state when cantilever 112 is in contact with contact108, a second state when cantilever 112 is in contact with contact 508,and/or a third state when cantilever 112 is in contact with neithercontact 108 nor contact 508. Of course the general layout of relay 100shown in FIG. 5 could be combined with any of the techniques and layoutsdescribed above to create new embodiments of relay 100.

It will be understood that many other embodiments could be formulatedwithout departing from the scope of the invention. For example, adouble-throw relay could be created by adding an additional contact 108that comes into contact with cantilever 112 when the cantilever is inits open state. Similarly, various topographies and geometries of relay100 could be formulated by varying the layout of the various components(such as pads 108 and 110 and cantilever 112).

The corresponding structures, materials, acts and equivalents of allelements in the claims below are intended to include any structure,material or acts for performing the functions in combination with otherclaimed elements as specifically claimed. Moreover, the steps recited inany method claims may be executed in any order. The scope of theinvention should be determined by the appended claims and their legalequivalents, rather than by the examples given above.

What is claimed is:
 1. A micro magnetic latching device, comprising: asubstrate; a moveable element supported by said substrate and having amagnetic material and a longitudinal axis; a first permanent magnetproducing a first magnetic field, which induces a magnetization in saidmagnetic material, said magnetization characterized by a magnetizationvector pointing in a direction along said longitudinal axis of saidmoveable element, wherein said first magnetic field is approximatelyperpendicular to said longitudinal axis; and an electromagnet producinga second magnetic field to switch said movable element between twostable states, wherein a temporary current through said electromagnetproduces said second magnetic field such that a component of said secondmagnetic field parallel to said longitudinal axis changes direction ofsaid magnetization vector thereby causing said movable element to switchbetween said two stable states.
 2. The device of claim 1, wherein saidmoveable element is supported by a staging layer supported by saidsubstrate.
 3. The device of claim 1, wherein said moveable element issupported by a hinge supported by said substrate.
 4. The device of claim1, wherein said second magnet comprises an electromagnet.
 5. The deviceof claim 4, wherein said electromagnet comprises a coil.
 6. The deviceof claim 5, wherein said coil is formed on said substrate.
 7. The deviceof claim 1, wherein said moveable element comprises a cantileversupported by a hinge on said substrate.
 8. The device of claim 7,wherein said hinge supports said cantilever at about a center positionalong the long axis.
 9. The device of claim 1, wherein said moveableelement is located at a first side of said substrate and said firstmagnet is located at a second side of said substrate.
 10. The device ofclaim 1, wherein said magnetic material comprises a high-permeabilitymaterial.
 11. The device of claim 10, wherein said high-permeabilitymaterial comprises a permalloy.
 12. A method of operating micro magneticlatching device, comprising the steps of: providing a moveable element,supported by a substrate, having a magnetic material and a longitudinalaxis; producing a first magnetic field with a first permanent magnet,which thereby induces a magnetization in the magnetic material, themagnetization characterized by a magnetization vector pointing in adirection along the longitudinal axis of the moveable element, the firstmagnetic field being approximately perpendicular to the longitudinalaxis; and producing a second magnetic field to switch the movableelement between two stable states, wherein only temporary application ofthe second magnetic field is required to change direction of themagnetization vector thereby causing the movable element to switchbetween the two stable states.
 13. The method of claim 12, wherein thesecond magnet comprises as an electromagnet.
 14. The method of claim 13,wherein the electromagnet as a coil.
 15. The method of claim 14, furthercomprising the step of forming the coil on the substrate.
 16. The methodof claim 12, wherein the moveable element as a cantilever supported by ahinge.
 17. The method of claim 16, wherein the cantilever is support bythe hinge at about a center position along the long axis.
 18. The methodof claim 12, further comprising the step of locating the moveableelement at a first side of the substrate and the first magnet at asecond side of the substrate.
 19. The method of claim 12, wherein themagnetic material as a high-permeability material.
 20. The method ofclaim 19, wherein the high-permeability material as a permalloy.